1. Field of the Invention
This invention relates to a liquid crystal display, and more particularly, to a liquid crystal display device wherein pattern defects generated during the formation process are eliminated to reduce the need for repairs.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) has a structure in which unit pixels are arranged horizontally and vertically each of the unit pixels includes a switching device consisting of a thin film transistor (TFT) and a pixel electrode for controlling a liquid crystal injected between substrates to transmit or reflect an incident light.
In the LCD, N×M unit pixels (wherein N and M are integers), each of which consists of a thin film transistors as a switching device and a pixel electrode coupled with the thin film transistor, are vertically and horizontally arranged in a matrix. N gate lines and M data lines transmitting signals to the gate electrodes and the source electrodes of the thin film transistors, respectively, are formed in such a manner to cross each other.
FIG. 1 is a plan view showing a structure of an LCD of the related art, and FIG. 2 is a section view of the related art LCD taken along the II-II′ line in FIG. 1. Referring to FIG. 1 and FIG. 2, in the related art LCD, N gate lines 13 and M data lines 21 are formed on a transparent substrate 11 in such a manner to cross each other, thereby defining N×M pixel areas. The gate lines 13 and the data lines 21 are made from a metal and have a gate insulating layer 17 therebetween to be electrically insulated from each other. The N×M pixel areas include N×M pixels, each of which is driven with a TFT as a switching device connected electrically to the gate line 13 and the data line 21.
The TFT consists of a gate electrode 15, a source electrode 23, a drain electrode 25, and a semiconductor layer 19 including an ohmic contact layer (not shown) and an active layer (not shown). The gate electrode 15 is connected to the gate line 13 while the source electrode 23 is connected to the data line 21. The drain electrode 25 is opposed to the source electrode 23 with the gate electrode 15 therebetween. The semiconductor layer 19 is formed on the gate insulating layer 17 in such a manner as to overlap the gate electrode 15 and the source and drain electrodes 23 and 25 of the TFT as well as the data line 21.
A passivation layer 26 is provided to cover the TFT having the structure as mentioned above. A transparent pixel electrode 29 electrically connected to the drain electrode 25 via a contact hole 27 is provided at a pixel area on the passivation layer 26.
However, the related art LCD has a problem in that, since it must be repaired upon the generation of pattern defects in the gate line and the semiconductor line, its process time is increased.